Krautwald M E, Müller H, Kaleta E F
Zentralbl Veterinarmed B. 1989 Aug;36(6):459-67. doi: 10.1111/j.1439-0450.1989.tb00628.x.
In order to get insight into the aetiology of French Moult (FM) and Budgerigar Fledgling Disease (BFD), and to determine relationships between the two diseases, 298 budgerigars from 49 different breeding flocks were examined. From all birds with BFD and from several birds with FM, viruses were isolated which produced characteristic cytopathic changes in chicken embryo fibroblasts. They were insensitive to chloroform treatment, and their replication was inhibited in the presence of 5-iododeoxyuridine. One of these isolates, from a bird exhibiting clinical signs of BFD, was determined by biochemical and biophysical methods to be a polyomavirus (BFDV). Nestling budgerigars 3 to 10 days of age, were inoculated with this BFDV isolate. They developed an acute systemic disease with high mortality rates, similar to naturally occurring infections. In this regard, BFDV differs markedly from all the other polyomaviruses known until now which only cause clinically asymptomatic, persistent infections in their natural hosts. Most of the birds examined with clinical signs of BFD or FM exhibited low titers of antibodies neutralizing the BFDV isolate, whereas in clinically healthy birds from flocks that never had any problems with FM or BFD, no antibodies against BFDV could be detected. On account of the results of our experiments described here we suspect that FM might be a milder, more protracted form of a BFDV infection.
为深入了解法国换羽症（FM）和虎皮鹦鹉雏鸟病（BFD）的病因，并确定这两种疾病之间的关系，对来自49个不同繁殖鸟群的298只虎皮鹦鹉进行了检查。从所有患有BFD的鸟以及几只患有FM的鸟中分离出了病毒，这些病毒在鸡胚成纤维细胞中产生了特征性的细胞病变。它们对氯仿处理不敏感，并且在5-碘脱氧尿苷存在的情况下其复制受到抑制。其中一个分离株来自一只表现出BFD临床症状的鸟，通过生化和生物物理方法确定为多瘤病毒（BFDV）。用这种BFDV分离株接种3至10日龄的雏虎皮鹦鹉。它们患上了一种急性全身性疾病，死亡率很高，类似于自然发生的感染。在这方面，BFDV与迄今为止已知的所有其他多瘤病毒明显不同，后者在其自然宿主中仅引起临床无症状的持续性感染。大多数表现出BFD或FM临床症状的检查鸟显示出中和BFDV分离株的抗体滴度较低，而在从未有过FM或BFD问题的鸟群中的临床健康鸟中，未检测到针对BFDV的抗体。根据我们在此描述的实验结果，我们怀疑FM可能是BFDV感染的一种较轻、病程较长的形式。
